1. Technical Field
The present invention relates to a turbine nozzle for a gas turbine and particularly relates to a first stage turbine nozzle airfoil profile.
2. Background of the Invention
In recent years, advanced gas turbines have trended toward increasing firing temperatures and efforts to improve cooling of the various turbine components. In a particular gas turbine design of the assignee, a high output turbine that uses air cooling is undergoing development. It will be appreciated that the design and construction of the turbine buckets and nozzles require optimized aerodynamic efficiency, as well as aerodynamic and mechanical loading.
In accordance with a preferred embodiment of the present invention, there is provided a unique airfoil profile for the nozzles of a turbine stage, preferably the first stage of a gas turbine. The nozzle airfoil profile is defined by a unique loci of points to achieve the necessary efficiency whereby improved turbine performance is obtained. These unique loci of points define the nominal airfoil profile and are identified by the X, Y and Z Cartesian coordinates of Table 1 which follows. The 1200 points for the coordinate values shown in Table 1 are for a cold, i.e., room temperature, profile at various planar cross sections of the nozzle airfoil along its length. The X and Y coordinates are given in distance dimensions, e.g., units of inches, and are joined smoothly at each Z location to form a smooth continuous airfoil cross section. The Z coordinates are given in nondimensionalized form from 0 to 1 along a nozzle stacking axis coincident with a radius from the axis of turbine rotation. By multiplying the airfoil height dimension, e.g., in inches, by the nondimensional Z value of Table 1 and adding that value to the root radius of the nozzle, the actual Z distance from the rotational axis, e.g., in inches, is obtained. Each defined cross section is then joined smoothly with adjacent cross sections to form the complete airfoil shape.
It will be appreciated that as each nozzle airfoil heats up in use, the profile will change as a result of stress and temperature. Thus, the cold or room temperature profile is given by the X, Y and Z coordinates for manufacturing purposes. Because the manufactured nozzle airfoil profile may be different from the nominal airfoil profile given by the following table, a distance of plus or minus 0.160 inches from the nominal profile in a direction normal to any surface location along the nominal profile defines the profile envelope for this nozzle airfoil. The envelope includes any possible airfoil surface coating process. The design is robust to this variation without impairment of the mechanical and aerodynamic functions.
It also will be appreciated that the airfoil can be scaled up or scaled down geometrically for introduction into similar turbine designs. Consequently, the X and Y coordinates in inches and the Z coordinates, when converted to inches, of the nominal airfoil profile given below are a function of the same constant or number. That is, the X and Y and optionally the Z coordinate values in inches may be multiplied or divided by the same constant or number to provide a scaled up or scaled down version of the nozzle airfoil profile while retaining the airfoil section shape.
In a preferred embodiment according to the present invention, there is provided a turbine nozzle having an airfoil shape in an envelope within xc2x10.160 inches in a direction normal to any airfoil surface location wherein the airfoil has a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and Z set forth in Table 1. Z is a nondimensional value along a nozzle stacking axis coincident with a radius from a turbine axis of rotation convertible to a Z distance in inches from said turbine axis by multiplying the Z value by a height of the airfoil and adding that product to a root radius of the nozzle. X and Y are distances in inches defining the airfoil profile at each distance Z, the profiles at the Z distances being joined smoothly with one another to form a complete airfoil shape.
In a further preferred embodiment according to the present invention, there is provided a turbine nozzle having an uncoated nominal airfoil profile substantially in accordance with Cartesian coordinate values of X, Y and Z set forth in Table 1. Z is a nondimensional value along a nozzle stacking axis coincident with a radius from a turbine axis of rotation convertible to a Z distance in inches from said turbine axis by multiplying the Z value by a height of the airfoil and adding that product to a root radius of the nozzle and wherein X and Y are distances in inches defining the airfoil profile at each distance Z, the profiles at the Z distances being joined smoothly with one another to form a complete airfoil shape, the X and Y distances being scalable as a function of the same constant or number to provide a scaled up or scaled down nozzle airfoil.
In a further preferred embodiment according to the present invention, there is provided a turbine including a turbine nozzle arrangement having a number of nozzles, each of the nozzles having an airfoil shape in an envelope within xc2x10.160 inches in a direction normal to any airfoil surface location wherein the airfoil has a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and Z set forth in Table 1, wherein Z is a nondimensional value along a nozzle centerline coincident with a radius from a turbine axis of rotation convertible to a Z distance in inches from said turbine axis by multiplying the Z value by a height of the airfoil and adding that product to a root radius of the nozzle, and wherein X and Y are distances in inches defining the airfoil profile at each distance Z, the profiles at the Z distances being joined smoothly with one another to form a complete airfoil shape.
In a further preferred embodiment according to the present invention, there is provided a turbine including a turbine nozzle arrangement having a number of nozzles, each of the nozzles having an uncoated nominal airfoil profile substantially in accordance with Cartesian coordinate values of X, Y and Z set forth in Table 1, wherein Z is a nondimensional value along a nozzle centerline coincident with a radius from a turbine axis of rotation convertible to a Z distance in inches from said turbine axis of rotation by miultiplying the Z value by a height of the airfoil and adding that product to a root radius of the nozzle and wherein X and Y are distances in inches defining the airfoil profile at each distance Z, the profiles at the Z distances being joined smoothly with one another to form a complete airfoil shape. The X and Y distances being scalable as a function of the same constant or number to provide a scaled up or scaled down nozzle airfoil.